TWI532706B - A method for producing diisobutylene with mixed C4 fraction as raw material - Google Patents

Description

Method for producing diisobutylene mixed with raw material C4 fraction

The present invention relates to a method for producing diisobutylene of a mixed C4 fraction as a raw material, which is described in more detail with respect to a solid acid catalyst, preferably a cerium oxide-alumina catalyst. The mixed C4 fraction is contacted, and after the oligomerization reaction of isobutene in the first-stage reaction, a method of performing a distillation operation to produce a high-purity diisobutylene having a high added value at a high reaction selectivity is employed.

The dimer of isobutylene is diisobutylene (hereinafter abbreviated as "DIB"), and is known as a raw material of an oxo alcohol, a raw material of isophthalic acid, a raw material of p-octyl phenol, a raw material of a rubber adhesion imparting agent, and an interface activity. The raw materials of the agent, even gasoline fuel additives, rubber drugs and the like are useful.

As a method for producing diisobutylene, in general, isobutylene from a FCC (flow contact decomposition) or a C4 fraction produced by an ethylene plant is selectively reacted with a sulfuric acid phase as isobutyl sulfate from 1-butene or 2 - Butene, butane, etc. are separated, followed by thermal decomposition to obtain diisobutylene. Alternatively, isobutylene is formed into MTBE (methyl tert-butyl ether) or TBA (third butyl alcohol) from the C4 fraction, and then decomposed to obtain diisobutylene which is 2-polymerized.

In the former, a large amount of oligomers of trimer or tetramer are formed in addition to the diisobutylene of the standard, and the reaction selectivity of DIB is low, and high price is required. Corrosion resistant material. Again, both have many and complicated steps.

On the other hand, Patent Document 1 discloses that a proton of a part of an acidic ion exchanger is replaced by a metal ion, and an oligomerization technique using isobutylene of an acidic ion exchange resin having a sulfonic acid group is used. In this technique, high-purity diisobutylene is obtained using the C4 mixed fraction as a raw material, but isobutylene exhibits only a low conversion rate, and the oligomerization catalyst and the ceria-alumina catalyst are completely different.

Further, Patent Document 2 discloses the use of a ceria-alumina catalyst, fuel, for example, to produce gasoline and/or kerosene. A technique for oligomerization of olefins of light oil. In this technique, the C4 mixed fraction is used as a raw material to carry out oligomerization when the conversion of isobutylene is 90% or more, or the conversion of 1-butene is 90%, and the conversion of 2-butene is 80%. The target is a polymer of C5 or higher. Product (the purity of diisobutylene is not described). Further, in the examples, the conversion of isobutylene was 97 to 100%, and the conversion of isobutylene was allowed to react in an extremely high field.

[prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2004-123714

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2006-28519

The present invention has been developed in this case, the purpose of which is to bring the mixed C4 fraction of the raw material into contact with the polymerization catalyst, and to carry out isobutene in the first-stage reaction. The oligomerization reaction provides a method of producing high purity DIB with high reaction selectivity.

The present inventors have obtained the following findings in order to achieve the above-mentioned objects and have been carefully studied.

It has been found that, as an oligomerization catalyst, a solid acid catalyst, preferably a ceria-alumina catalyst, is brought into contact with the mixed C4 fraction, and the conversion of isobutylene in the mixed C4 fraction is controlled at a predetermined rate. Within the range specified in the range, DIB is obtained at a high reaction selectivity, and then a high-purity DIB is obtained by performing a predetermined distillation operation on the reaction product.

The present invention is based on the accomplishment of this finding.

That is, the present invention provides: [1] A method for producing diisobutylene, which is a method for producing diisobutylene by bringing a mixed C4 fraction of a raw material into contact with a solid acid catalyst, which comprises the following (a) to ( Step c): (a) an oligomerization reaction step of isobutylene, (b) a step of separating and separating the unreacted C4 fraction from the oligomer fraction containing the produced C8 fraction, and (c) a C8 fraction The step of distilling and purifying the diisobutylene in the step, and in the step (a), controlling the conversion ratio of the isobutylene in the mixed C4 fraction to be in the range of 60 to 95%, [2] as described in the above [1] The method for producing isobutylene, wherein the solid acid catalyst is a cerium oxide-alumina catalyst, and the method for producing a diisobutylene according to the above [1], wherein the isobutylene in the step (a) The reaction conditions of the oligomerization reaction step are as follows: the WHS fraction of the mixed C4 fraction to the solid acid catalyst (the ratio of the mass of the supplied raw material to the mass of the catalyst per hour) is 0.1 to 5 hr ^-1 , and the reaction temperature is 150 ° C or less. And the reaction pressure is 0.2 MPa or more, and the pressure of the raw material can be liquefied The method for producing diisobutylene according to any one of the above [1] to [3], wherein (c) the step of purifying the diisobutylene in the C8 fraction by distillation, the content of the C4 fraction is obtained. It is 1% by mass or less and has a purity of 95% by mass or more of diisobutylene.

According to the method for producing DIB of the present invention, as the oligomerization catalyst, a solid acid catalyst, preferably a ceria-alumina catalyst, is used to control the isobutene in the mixed C4 fraction when it is brought into contact with the mixed C4 fraction. The conversion rate is within a predetermined range within a predetermined range, and at the same time, a DIB having a high reaction selectivity and high purity can be efficiently obtained by performing a predetermined distillation operation on the reaction product.

The method for producing DIB according to the present invention is a method for producing diisobutylene by bringing a mixed C4 fraction of a raw material into contact with a solid acid catalyst, and comprising the following steps (a) to (c): (a) an oligomerization reaction step of isobutylene, (b) a step of separating and separating an unreacted C4 fraction from an oligomer fraction containing the produced C8 fraction, and (c) performing diisobutylene in the C8 fraction The step of purifying and purifying, and in the above step (a), controlling the conversion of isobutylene in the mixed C4 fraction to be in the range of 60 to 95%.

[mixed C4 fraction]

In the method for producing DIB of the present invention, a mixed C4 fraction is used as a raw material.

The mixed C4 fraction may, for example, be an olefin fraction produced by an FCC process, a diene component extracted from a fraction produced in a gas oil cracking furnace, or optionally subjected to hydrogenation to remove an olefin fraction, and the like, and mixed in any ratio. Also available. Further, for the known methods such as distillation, the content of the specific fraction may be adjusted to increase or decrease. For example, it can be used in a light oil cracking furnace to produce a residue or a FCC-C4 fraction from the C4 fraction for distillation (or reactive distillation) to remove n-butenes and n-butanes. Concentration of isobutylene-isobutane fraction.

The mixed C4 fraction generally contains components such as 1-butene, trans-2-butene, cis-2-butene, isobutylene, n-butane, isobutane, butadiene.

(Prepared before mixing C4 fraction)

In the manufacturing method of the DIB of the present invention, the mixed C4 fraction of the raw materials is The application is treated as shown in the following (1) to (3) to remove impurities. It is preferred to purify it.

(1) The cause of the decrease in the activity of the catalyst or the decrease in the purity of the diisobutylene is a diene such as butadiene in the mixed C4 fraction, which may be an extraction solvent such as N,N-dimethylformamide or acetonitrile. Remove. Further, if necessary, a hydrogenation catalyst such as Pd or Ni may be selectively added to hydrogenate to lower the diene. Generally, it is based on 1000 mass ppm or less.

(2) Sulfur which causes the decrease in catalytic activity. The basic nitrogen fraction can be removed by washing with water or a sorbent of activated alumina or activated carbon, molecular sieve or the like.

(3) The C3 fraction which causes the decrease in the purity of diisobutylene can be removed from the top of the column by distillation.

[(a) Oligomerization reaction step of isobutylene]

In the method for producing DIB of the present invention, the solid acid catalyst is preferably a method for producing DIB by contacting the mixed C4 fraction of the raw material obtained by pretreatment, and the oligomerization of the isobutylene in the step (a). The physicochemical reaction step controls the conversion of isobutylene in the mixed C4 fraction to be in the range of 60 to 95%.

When the conversion of isobutylene exceeds 95%, the addition of 2-butene to 2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-2-pentene The olefin or 2-butene reacts with a heavy component such as a C8 component or even a trimer or a tetramer, and it is impossible to carry out high purity of diisobutylene by subsequent distillation. When the conversion of isobutylene is less than 60%, the amount of unreacted raw materials increases, and it is impossible to increase the yield. Rate to make diisobutylene. From the above viewpoints, the conversion of isobutylene is preferably 65 to 90%, and more preferably 70 to 90%.

In addition, the control of the conversion of isobutylene will be described in detail later.

(solid acid catalyst)

In the DIB production method of the present invention, the solid acid catalyst used as the oligomerization reaction catalyst may, for example, be cerium oxide-alumina, cerium oxide-magnesia, cerium oxide-boron oxide or aluminum oxide. - boron oxide, aluminum chloride, fluorided alumina, hydrochloric acid, sulfuric acid, phosphoric acid, BF _3, etc. attached to cerium oxide gel or alumina gel, cation exchange resin, synthetic zeolite, heteropoly acid (Heteropoly Acid), zirconia-based composite metal oxide such as molybdenum oxide/zirconia or tungsten oxide/zirconia, and clay minerals such as acid clay, bentonite, kaolin, and montmorillonite. These solid acid catalysts may be used alone or in combination of two or more. Among them, cerium oxide-aluminum oxide is particularly suitable.

The cerium oxide-alumina catalyst is a deposition method in which alumina is adhered to a cerium oxide gel by a solution of Al ₂ (SO ₄ ) ₃ and NH ₄ OH, or by adding sodium citrate The (water glass) solution is produced by a method such as a precipitation method of an Al ₂ (SO ₄ ) ₃ solution. The gel is fired at a temperature of about 550 ° C, and its activity is extremely large.

As the cerium oxide-alumina catalyst, those having the following properties can be usually used.

. SiO ₂ /Al ₂ O ₃ mass ratio: 2~20

. Determination of average pore diameter by nitrogen adsorption method: 2~10nm

. Determination of total pore volume by nitrogen adsorption method: 0.2~1mL/g

. BET specific surface area: 200~600m ² /g

(Control of isobutylene conversion rate)

The control of the conversion of isobutylene can be carried out within the range of reaction conditions described below.

(1) For the solid acid catalyst, the WHSV of the C4 fraction (the mass of the raw material supplied for the catalyst mass per hour) is preferably 0.1 to 5 hr ^{-1 and more} preferably 0.2 to 2 hr ^-1 . When this WHSV of 0.1hr ^-1 or more, the conversion rate of isobutene can be maintained at 95% or less, on the other hand, when 5hr ^-1 or less of isobutylene conversion can be maintained at 60% or more.

(2) The reaction temperature is preferably 150 ° C or less, more preferably 25 to 100 ° C. When the reaction temperature is 25 ° C or more, an appropriate reaction rate is required, and a large amount of catalyst is not required. On the other hand, when it is 150 ° C or less, the reaction selectivity of DIB can be suppressed from decreasing, and a high-purity DIB can be obtained.

(3) The reaction pressure is preferably 0.2 MPa or more, and the raw material may be at a pressure which can be liquefied.

(4) When performing the reaction, a heat insulating reflector or a multitubular reactor or the like can be used. The control of the reaction temperature (heat removal) can be carried out by recycling the reactor for the reaction product (supplied with the raw material) or diluting the raw material with a diluent. When the reactor for the reaction product liquid is recycled, the recycled liquid is preferably 0 to 4 mass times, and more preferably 0 to 3 mass ratio. When the amount of recirculation is 4 or less, the reaction rate is not reduced because the concentration of the raw material is lowered, and a large amount of catalyst is not required.

Further, the reactor and the reaction form used in the oligomerization reaction of isobutylene are not particularly limited, and a batch type, a semi-batch type, a continuous flow type reaction via a tank type reactor, or a fixed bed flow may be employed. Continuous flow reaction of a circulating reactor in a bed or a moving bed.

In the manufacturing method of the DIB of the invention, as the step (b), the step of separating the unreacted C4 fraction from the oligomer fraction containing the produced C8 fraction by distillation, and as the step (c), The DIB in the C8 fraction is subjected to a distillation purification step.

[(b) Steps]

The step (b) is a step of distilling and separating the unreacted C4 fraction in the reaction product liquid from the oligomer fraction containing the C8 fraction formed in the oligomerization reaction.

In the step (b), the reaction product is supplied to the distillation column, and the distillation conditions (reflow ratio (R/D), pressure, etc.) are adjusted so that the C4 fraction in the bottom liquid becomes 1% by mass or less. The top of the column was removed as a C4 fraction of unreacted raw material to obtain a diisobutylene-containing polymer in the C8 fraction as a bottom liquid.

[(c) Steps]

The step (c) is a step of purifying and purifying diisobutylene in the C8 fraction obtained in the above step (b), and the bottom liquid containing diisobutylene is supplied to the distillation column in the step (b) A C8 fraction based on diisobutylene is obtained, and a polymer having a trimer or higher is obtained from the bottom of the column. The ingredient of the Lord.

In the step (c), diisobutylene having a C4 fraction content of 1% by mass or less and a purity of 95% by mass or more can be obtained.

[Use of diisobutylene]

Diisobutylene (2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-2-pentene) obtained by the method for producing DIB of the present invention, for example, as an oxo alcohol The raw material, the raw material of isononic acid, the raw material of p-octylphenol, the raw material of the rubber adhesion-imparting agent, the raw material of the surfactant, the gasoline fuel additive, and the rubber drug are used by the user.

[Examples]

The invention is further illustrated by the examples, which are not intended to be limited by the examples.

Examples 1 to 3 and Comparative Example 1

The diene component of butadiene or the like in the mixed C4 fraction obtained from the cracking of naphtha is selectively extracted in dimethylformaldehyde, and then selectively hydrogenated and diene in a commercially available Pd catalyst. The concentration is 10 mass ppm or less. Then, when the S component and the N component are 5 mass ppm or less by water washing, they are removed. Further, the C3 component is removed through the top of the column via continuous distillation as a raw material for the production of diisobutylene. (Material composition in Table 1).

Cerium oxide-alumina catalyst as a polymerization catalyst [SiO ₂ /Al ₂ O ₃ mass ratio: 9, average pore diameter: 6 nm, total pore volume: 0.5 mL/g, BET specific surface area: 400 m ² / g] Filled in a tubular reactor to carry out a fixed bed continuous reaction. The reactor is heated in a heating pack and the catalyst bed is controlled to be isothermal. The reaction conditions and reaction results are shown in Table 1.

In Examples 1 to 3, the reaction pressure and WHSV were fixed, and the reaction temperature was changed to cause the isobutylene conversion rate to be less than 95%. On the other hand, as a comparative example, in the same manner as in Examples 1 to 3, the reaction pressure and WHSV were fixed, and the reaction temperature was 80 ° C, and the conversion of isobutylene was 98%.

Further, the obtained reaction product liquid was subjected to continuous distillation for 18 stages, R/D: 0.29, and overhead pressure of 0.38 MPa to remove the C4 component of the unreacted raw material, followed by a bottom liquid containing diisobutylene. As the feed liquid, a C8 component containing diisobutylene was obtained through the top of the column by continuous distillation of 40 stages, R/D: 5, and column top pressure of 0.65 MPa. The concentration of the obtained C8 component is diisobutylene, that is, the concentration of 2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-2-pentene is shown in the lowermost part of Table 1. .

According to Tables 1 to 3 in which the isobutylene conversion ratio was 74 to 93%, it was judged that a high-purity product having a diisobutylene concentration of 95% or more was obtained. On the other hand, in the comparative example in which the conversion of isobutylene was 98%, the purity of diisobutylene was 90%.

[Industrial use possibility]

The method for producing DIB of the present invention is carried out by contacting a mixed C4 fraction of a raw material with a solid acid catalyst, preferably a ceria-alumina catalyst, and performing an oligomerization reaction of isobutylene in a first-stage reaction. Via Shi By performing a distillation operation, high-purity diisobutylene having a high added value can be produced with a high reaction selectivity.

Claims (3)

A method for producing diisobutylene, which is a method for producing diisobutylene by bringing a mixed C4 fraction of a raw material into contact with a solid acid catalyst, and comprising the following steps (a) to (c): (a) isobutylene An oligomerization reaction step of (isobutene), (b) a step of separating and separating an unreacted C4 fraction from an oligomer fraction containing the C8 fraction formed, and (c) diisobutylene in a C8 fraction The step of performing distillation purification, and in the above step (a), the reaction condition of the oligomerization reaction step of isobutene is mixing the WH4 of the C4 fraction with the solid acid catalyst (the quality of the raw material supplied per hour) The ratio of the mass to the catalyst is 0.1 to 5 hr ^-1 , the reaction temperature is 150 ° C or less, and the reaction pressure is 0.2 MPa or more, and the pressure at which the raw material can be liquefied, and the conversion of isobutene in the mixed C4 fraction is controlled. The rate is in the range of 60 to 95%. The method for producing an isobutylene according to claim 1, wherein the solid acid catalyst is a cerium oxide-alumina catalyst. The method for producing isobutylene according to claim 1 or 2, wherein in the step (c) of distilling and purifying the diisobutylene in the C8 fraction, the content of the C4 fraction is 1% by mass or less and the purity is 95% by mass. The above two isobutylene.